net/mac80211/rate.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/rtnetlink.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include "rate.h"
 #include "ieee80211_i.h"
 #include "debugfs.h"

 struct rate_control_alg {
 	struct list_head list;
 	const struct rate_control_ops *ops;
 };

 static LIST_HEAD(rate_ctrl_algs);
 static DEFINE_MUTEX(rate_ctrl_mutex);

 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
 module_param(ieee80211_default_rc_algo, charp, 0644);
 MODULE_PARM_DESC(ieee80211_default_rc_algo,
 		 "Default rate control algorithm for mac80211 to use");

 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
 {
 	struct rate_control_alg *alg;

 	if (!ops->name)
 		return -EINVAL;

 	mutex_lock(&rate_ctrl_mutex);
 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
 		if (!strcmp(alg->ops->name, ops->name)) {
 			/* don't register an algorithm twice */
 			WARN_ON(1);
 			mutex_unlock(&rate_ctrl_mutex);
 			return -EALREADY;
 		}
 	}

 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
 	if (alg == NULL) {
 		mutex_unlock(&rate_ctrl_mutex);
 		return -ENOMEM;
 	}
 	alg->ops = ops;

 	list_add_tail(&alg->list, &rate_ctrl_algs);
 	mutex_unlock(&rate_ctrl_mutex);

 	return 0;
 }
 EXPORT_SYMBOL(ieee80211_rate_control_register);

 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
 {
 	struct rate_control_alg *alg;

 	mutex_lock(&rate_ctrl_mutex);
 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
 		if (alg->ops == ops) {
 			list_del(&alg->list);
 			kfree(alg);
 			break;
 		}
 	}
 	mutex_unlock(&rate_ctrl_mutex);
 }
 EXPORT_SYMBOL(ieee80211_rate_control_unregister);

 static const struct rate_control_ops *
 ieee80211_try_rate_control_ops_get(const char *name)
 {
 	struct rate_control_alg *alg;
 	const struct rate_control_ops *ops = NULL;

 	if (!name)
 		return NULL;

 	mutex_lock(&rate_ctrl_mutex);
 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
 		if (!strcmp(alg->ops->name, name)) {
 			ops = alg->ops;
 			break;
 		}
 	}
 	mutex_unlock(&rate_ctrl_mutex);
 	return ops;
 }

 /* Get the rate control algorithm. */
 static const struct rate_control_ops *
 ieee80211_rate_control_ops_get(const char *name)
 {
 	const struct rate_control_ops *ops;
 	const char *alg_name;

 	kparam_block_sysfs_write(ieee80211_default_rc_algo);
 	if (!name)
 		alg_name = ieee80211_default_rc_algo;
 	else
 		alg_name = name;

 	ops = ieee80211_try_rate_control_ops_get(alg_name);
 	if (!ops && name)
 		/* try default if specific alg requested but not found */
 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);

 	/* try built-in one if specific alg requested but not found */
 	if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
 	kparam_unblock_sysfs_write(ieee80211_default_rc_algo);

 	return ops;
 }

 #ifdef CONFIG_MAC80211_DEBUGFS
 static ssize_t rcname_read(struct file *file, char __user *userbuf,
 			   size_t count, loff_t *ppos)
 {
 	struct rate_control_ref *ref = file->private_data;
 	int len = strlen(ref->ops->name);

 	return simple_read_from_buffer(userbuf, count, ppos,
 				       ref->ops->name, len);
 }

 static const struct file_operations rcname_ops = {
 	.read = rcname_read,
 	.open = simple_open,
 	.llseek = default_llseek,
 };
 #endif

 static struct rate_control_ref *rate_control_alloc(const char *name,
 					    struct ieee80211_local *local)
 {
 	struct dentry *debugfsdir = NULL;
 	struct rate_control_ref *ref;

 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 	if (!ref)
 		return NULL;
 	ref->local = local;
 	ref->ops = ieee80211_rate_control_ops_get(name);
 	if (!ref->ops)
 		goto free;

 #ifdef CONFIG_MAC80211_DEBUGFS
 	debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
 	local->debugfs.rcdir = debugfsdir;
 	debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
 #endif

 	ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
 	if (!ref->priv)
 		goto free;
 	return ref;

 free:
 	kfree(ref);
 	return NULL;
 }

 static void rate_control_free(struct rate_control_ref *ctrl_ref)
 {
 	ctrl_ref->ops->free(ctrl_ref->priv);

 #ifdef CONFIG_MAC80211_DEBUGFS
 	debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
 	ctrl_ref->local->debugfs.rcdir = NULL;
 #endif

 	kfree(ctrl_ref);
 }

 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
 {
 	struct sk_buff *skb = txrc->skb;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;

 	fc = hdr->frame_control;

 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
 		!ieee80211_is_data(fc);
 }

 static void rc_send_low_basicrate(s8 *idx, u32 basic_rates,
 				  struct ieee80211_supported_band *sband)
 {
 	u8 i;

 	if (basic_rates == 0)
 		return; /* assume basic rates unknown and accept rate */
 	if (*idx < 0)
 		return;
 	if (basic_rates & (1 << *idx))
 		return; /* selected rate is a basic rate */

 	for (i = *idx + 1; i <= sband->n_bitrates; i++) {
 		if (basic_rates & (1 << i)) {
 			*idx = i;
 			return;
 		}
 	}

 	/* could not find a basic rate; use original selection */
 }

 static void __rate_control_send_low(struct ieee80211_hw *hw,
 				    struct ieee80211_supported_band *sband,
 				    struct ieee80211_sta *sta,
 				    struct ieee80211_tx_info *info,
 				    u32 rate_mask)
 {
 	int i;
 	u32 rate_flags =
 		ieee80211_chandef_rate_flags(&hw->conf.chandef);

 	if ((sband->band == IEEE80211_BAND_2GHZ) &&
 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
 		rate_flags |= IEEE80211_RATE_ERP_G;

 	info->control.rates[0].idx = 0;
 	for (i = 0; i < sband->n_bitrates; i++) {
 		if (!(rate_mask & BIT(i)))
 			continue;

 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
 			continue;

 		if (!rate_supported(sta, sband->band, i))
 			continue;

 		info->control.rates[0].idx = i;
 		break;
 	}
 	WARN_ON_ONCE(i == sband->n_bitrates);

 	info->control.rates[0].count =
 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
 		1 : hw->max_rate_tries;

 	info->control.skip_table = 1;
 }


 bool rate_control_send_low(struct ieee80211_sta *pubsta,
 			   void *priv_sta,
 			   struct ieee80211_tx_rate_control *txrc)
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 	struct ieee80211_supported_band *sband = txrc->sband;
 	struct sta_info *sta;
 	int mcast_rate;
 	bool use_basicrate = false;

 	if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
 					txrc->rate_idx_mask);

 		if (!pubsta && txrc->bss) {
 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
 			if (mcast_rate > 0) {
 				info->control.rates[0].idx = mcast_rate - 1;
 				return true;
 			}
 			use_basicrate = true;
 		} else if (pubsta) {
 			sta = container_of(pubsta, struct sta_info, sta);
 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 				use_basicrate = true;
 		}

 		if (use_basicrate)
 			rc_send_low_basicrate(&info->control.rates[0].idx,
 					      txrc->bss_conf->basic_rates,
 					      sband);

 		return true;
 	}
 	return false;
 }
 EXPORT_SYMBOL(rate_control_send_low);

 static bool rate_idx_match_legacy_mask(struct ieee80211_tx_rate *rate,
 				       int n_bitrates, u32 mask)
 {
 	int j;

 	/* See whether the selected rate or anything below it is allowed. */
 	for (j = rate->idx; j >= 0; j--) {
 		if (mask & (1 << j)) {
 			/* Okay, found a suitable rate. Use it. */
 			rate->idx = j;
 			return true;
 		}
 	}

 	/* Try to find a higher rate that would be allowed */
 	for (j = rate->idx + 1; j < n_bitrates; j++) {
 		if (mask & (1 << j)) {
 			/* Okay, found a suitable rate. Use it. */
 			rate->idx = j;
 			return true;
 		}
 	}
 	return false;
 }

 static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
 				    u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 {
 	int i, j;
 	int ridx, rbit;

 	ridx = rate->idx / 8;
 	rbit = rate->idx % 8;

 	/* sanity check */
 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
 		return false;

 	/* See whether the selected rate or anything below it is allowed. */
 	for (i = ridx; i >= 0; i--) {
 		for (j = rbit; j >= 0; j--)
 			if (mcs_mask[i] & BIT(j)) {
 				rate->idx = i * 8 + j;
 				return true;
 			}
 		rbit = 7;
 	}

 	/* Try to find a higher rate that would be allowed */
 	ridx = (rate->idx + 1) / 8;
 	rbit = (rate->idx + 1) % 8;

 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
 		for (j = rbit; j < 8; j++)
 			if (mcs_mask[i] & BIT(j)) {
 				rate->idx = i * 8 + j;
 				return true;
 			}
 		rbit = 0;
 	}
 	return false;
 }


 static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
 				struct ieee80211_supported_band *sband,
 				enum nl80211_chan_width chan_width,
 				u32 mask,
 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 {
 	struct ieee80211_tx_rate alt_rate;

 	/* handle HT rates */
 	if (rate->flags & IEEE80211_TX_RC_MCS) {
 		if (rate_idx_match_mcs_mask(rate, mcs_mask))
 			return;

 		/* also try the legacy rates. */
 		alt_rate.idx = 0;
 		/* keep protection flags */
 		alt_rate.flags = rate->flags &
 				 (IEEE80211_TX_RC_USE_RTS_CTS |
 				  IEEE80211_TX_RC_USE_CTS_PROTECT |
 				  IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 		alt_rate.count = rate->count;
 		if (rate_idx_match_legacy_mask(&alt_rate,
 					       sband->n_bitrates, mask)) {
 			*rate = alt_rate;
 			return;
 		}
 	} else if (!(rate->flags & IEEE80211_TX_RC_VHT_MCS)) {
 		/* handle legacy rates */
 		if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
 			return;

 		/* if HT BSS, and we handle a data frame, also try HT rates */
 		switch (chan_width) {
 		case NL80211_CHAN_WIDTH_20_NOHT:
 		case NL80211_CHAN_WIDTH_5:
 		case NL80211_CHAN_WIDTH_10:
 			return;
 		default:
 			break;
 		}

 		alt_rate.idx = 0;
 		/* keep protection flags */
 		alt_rate.flags = rate->flags &
 				 (IEEE80211_TX_RC_USE_RTS_CTS |
 				  IEEE80211_TX_RC_USE_CTS_PROTECT |
 				  IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 		alt_rate.count = rate->count;

 		alt_rate.flags |= IEEE80211_TX_RC_MCS;

 		if (chan_width == NL80211_CHAN_WIDTH_40)
 			alt_rate.flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;

 		if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
 			*rate = alt_rate;
 			return;
 		}
 	}

 	/*
 	 * Uh.. No suitable rate exists. This should not really happen with
 	 * sane TX rate mask configurations. However, should someone manage to
 	 * configure supported rates and TX rate mask in incompatible way,
 	 * allow the frame to be transmitted with whatever the rate control
 	 * selected.
 	 */
 }

 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
 				struct ieee80211_supported_band *sband,
 				struct ieee80211_tx_info *info,
 				struct ieee80211_tx_rate *rates,
 				int max_rates)
 {
 	struct ieee80211_rate *rate;
 	bool inval = false;
 	int i;

 	/*
 	 * Set up the RTS/CTS rate as the fastest basic rate
 	 * that is not faster than the data rate unless there
 	 * is no basic rate slower than the data rate, in which
 	 * case we pick the slowest basic rate
 	 *
 	 * XXX: Should this check all retry rates?
 	 */
 	if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
 		u32 basic_rates = vif->bss_conf.basic_rates;
 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;

 		rate = &sband->bitrates[rates[0].idx];

 		for (i = 0; i < sband->n_bitrates; i++) {
 			/* must be a basic rate */
 			if (!(basic_rates & BIT(i)))
 				continue;
 			/* must not be faster than the data rate */
 			if (sband->bitrates[i].bitrate > rate->bitrate)
 				continue;
 			/* maximum */
 			if (sband->bitrates[baserate].bitrate <
 			     sband->bitrates[i].bitrate)
 				baserate = i;
 		}

 		info->control.rts_cts_rate_idx = baserate;
 	}

 	for (i = 0; i < max_rates; i++) {
 		/*
 		 * make sure there's no valid rate following
 		 * an invalid one, just in case drivers don't
 		 * take the API seriously to stop at -1.
 		 */
 		if (inval) {
 			rates[i].idx = -1;
 			continue;
 		}
 		if (rates[i].idx < 0) {
 			inval = true;
 			continue;
 		}

 		/*
 		 * For now assume MCS is already set up correctly, this
 		 * needs to be fixed.
 		 */
 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
 			WARN_ON(rates[i].idx > 76);

 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 			    info->control.use_cts_prot)
 				rates[i].flags |=
 					IEEE80211_TX_RC_USE_CTS_PROTECT;
 			continue;
 		}

 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
 			continue;
 		}

 		/* set up RTS protection if desired */
 		if (info->control.use_rts) {
 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 			info->control.use_cts_prot = false;
 		}

 		/* RC is busted */
 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
 			rates[i].idx = -1;
 			continue;
 		}

 		rate = &sband->bitrates[rates[i].idx];

 		/* set up short preamble */
 		if (info->control.short_preamble &&
 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;

 		/* set up G protection */
 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 		    info->control.use_cts_prot &&
 		    rate->flags & IEEE80211_RATE_ERP_G)
 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
 	}
 }


 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
 					struct ieee80211_tx_info *info,
 					struct ieee80211_tx_rate *rates,
 					int max_rates)
 {
 	struct ieee80211_sta_rates *ratetbl = NULL;
 	int i;

 	if (sta && !info->control.skip_table)
 		ratetbl = rcu_dereference(sta->rates);

 	/* Fill remaining rate slots with data from the sta rate table. */
 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
 	for (i = 0; i < max_rates; i++) {
 		if (i < ARRAY_SIZE(info->control.rates) &&
 		    info->control.rates[i].idx >= 0 &&
 		    info->control.rates[i].count) {
 			if (rates != info->control.rates)
 				rates[i] = info->control.rates[i];
 		} else if (ratetbl) {
 			rates[i].idx = ratetbl->rate[i].idx;
 			rates[i].flags = ratetbl->rate[i].flags;
 			if (info->control.use_rts)
 				rates[i].count = ratetbl->rate[i].count_rts;
 			else if (info->control.use_cts_prot)
 				rates[i].count = ratetbl->rate[i].count_cts;
 			else
 				rates[i].count = ratetbl->rate[i].count;
 		} else {
 			rates[i].idx = -1;
 			rates[i].count = 0;
 		}

 		if (rates[i].idx < 0 || !rates[i].count)
 			break;
 	}
 }

 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
 				    struct ieee80211_sta *sta,
 				    struct ieee80211_supported_band *sband,
 				    struct ieee80211_tx_info *info,
 				    struct ieee80211_tx_rate *rates,
 				    int max_rates)
 {
 	enum nl80211_chan_width chan_width;
 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
 	bool has_mcs_mask;
 	u32 mask;
 	u32 rate_flags;
 	int i;

 	/*
 	 * Try to enforce the rateidx mask the user wanted. skip this if the
 	 * default mask (allow all rates) is used to save some processing for
 	 * the common case.
 	 */
 	mask = sdata->rc_rateidx_mask[info->band];
 	has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
 	rate_flags =
 		ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
 	for (i = 0; i < sband->n_bitrates; i++)
 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
 			mask &= ~BIT(i);

 	if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
 		return;

 	if (has_mcs_mask)
 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
 		       sizeof(mcs_mask));
 	else
 		memset(mcs_mask, 0xff, sizeof(mcs_mask));

 	if (sta) {
 		/* Filter out rates that the STA does not support */
 		mask &= sta->supp_rates[info->band];
 		for (i = 0; i < sizeof(mcs_mask); i++)
 			mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
 	}

 	/*
 	 * Make sure the rate index selected for each TX rate is
 	 * included in the configured mask and change the rate indexes
 	 * if needed.
 	 */
 	chan_width = sdata->vif.bss_conf.chandef.width;
 	for (i = 0; i < max_rates; i++) {
 		/* Skip invalid rates */
 		if (rates[i].idx < 0)
 			break;

 		rate_idx_match_mask(&rates[i], sband, chan_width, mask,
 				    mcs_mask);
 	}
 }

 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
 			    struct ieee80211_sta *sta,
 			    struct sk_buff *skb,
 			    struct ieee80211_tx_rate *dest,
 			    int max_rates)
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_supported_band *sband;

 	rate_control_fill_sta_table(sta, info, dest, max_rates);

 	if (!vif)
 		return;

 	sdata = vif_to_sdata(vif);
 	sband = sdata->local->hw.wiphy->bands[info->band];

 	if (ieee80211_is_data(hdr->frame_control))
 		rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);

 	if (dest[0].idx < 0)
 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
 					sdata->rc_rateidx_mask[info->band]);

 	if (sta)
 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
 }
 EXPORT_SYMBOL(ieee80211_get_tx_rates);

 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 			   struct sta_info *sta,
 			   struct ieee80211_tx_rate_control *txrc)
 {
 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
 	void *priv_sta = NULL;
 	struct ieee80211_sta *ista = NULL;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 	int i;

 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
 		ista = &sta->sta;
 		priv_sta = sta->rate_ctrl_priv;
 	}

 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 		info->control.rates[i].idx = -1;
 		info->control.rates[i].flags = 0;
 		info->control.rates[i].count = 0;
 	}

 	if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
 		return;

 	ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);

 	if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
 		return;

 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
 			       info->control.rates,
 			       ARRAY_SIZE(info->control.rates));
 }

 int rate_control_set_rates(struct ieee80211_hw *hw,
 			   struct ieee80211_sta *pubsta,
 			   struct ieee80211_sta_rates *rates)
 {
 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 	struct ieee80211_sta_rates *old;

 	/*
 	 * mac80211 guarantees that this function will not be called
 	 * concurrently, so the following RCU access is safe, even without
 	 * extra locking. This can not be checked easily, so we just set
 	 * the condition to true.
 	 */
 	old = rcu_dereference_protected(pubsta->rates, true);
 	rcu_assign_pointer(pubsta->rates, rates);
 	if (old)
 		kfree_rcu(old, rcu_head);

 	drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);

 	return 0;
 }
 EXPORT_SYMBOL(rate_control_set_rates);

 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 				 const char *name)
 {
 	struct rate_control_ref *ref;

 	ASSERT_RTNL();

 	if (local->open_count)
 		return -EBUSY;

 	if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
 		if (WARN_ON(!local->ops->set_rts_threshold))
 			return -EINVAL;
 		return 0;
 	}

 	ref = rate_control_alloc(name, local);
 	if (!ref) {
 		wiphy_warn(local->hw.wiphy,
 			   "Failed to select rate control algorithm\n");
 		return -ENOENT;
 	}

 	WARN_ON(local->rate_ctrl);
 	local->rate_ctrl = ref;

 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
 		    ref->ops->name);

 	return 0;
 }

 void rate_control_deinitialize(struct ieee80211_local *local)
 {
 	struct rate_control_ref *ref;

 	ref = local->rate_ctrl;

 	if (!ref)
 		return;

 	local->rate_ctrl = NULL;
 	rate_control_free(ref);
 }
	/*
	* Copyright 2002-2005, Instant802 Networks, Inc.
	* Copyright 2005-2006, Devicescape Software, Inc.
	* Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/rtnetlink.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include "rate.h"
	#include "ieee80211_i.h"
	#include "debugfs.h"

	struct rate_control_alg {
	struct list_head list;
	const struct rate_control_ops *ops;
	};

	static LIST_HEAD(rate_ctrl_algs);
	static DEFINE_MUTEX(rate_ctrl_mutex);

	static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
	module_param(ieee80211_default_rc_algo, charp, 0644);
	MODULE_PARM_DESC(ieee80211_default_rc_algo,
	"Default rate control algorithm for mac80211 to use");

	int ieee80211_rate_control_register(const struct rate_control_ops *ops)
	{
	struct rate_control_alg *alg;

	if (!ops->name)
	return -EINVAL;

	mutex_lock(&rate_ctrl_mutex);
	list_for_each_entry(alg, &rate_ctrl_algs, list) {
	if (!strcmp(alg->ops->name, ops->name)) {
	/* don't register an algorithm twice */
	WARN_ON(1);
	mutex_unlock(&rate_ctrl_mutex);
	return -EALREADY;
	}
	}

	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
	if (alg == NULL) {
	mutex_unlock(&rate_ctrl_mutex);
	return -ENOMEM;
	}
	alg->ops = ops;

	list_add_tail(&alg->list, &rate_ctrl_algs);
	mutex_unlock(&rate_ctrl_mutex);

	return 0;
	}
	EXPORT_SYMBOL(ieee80211_rate_control_register);

	void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
	{
	struct rate_control_alg *alg;

	mutex_lock(&rate_ctrl_mutex);
	list_for_each_entry(alg, &rate_ctrl_algs, list) {
	if (alg->ops == ops) {
	list_del(&alg->list);
	kfree(alg);
	break;
	}
	}
	mutex_unlock(&rate_ctrl_mutex);
	}
	EXPORT_SYMBOL(ieee80211_rate_control_unregister);

	static const struct rate_control_ops *
	ieee80211_try_rate_control_ops_get(const char *name)
	{
	struct rate_control_alg *alg;
	const struct rate_control_ops *ops = NULL;

	if (!name)
	return NULL;

	mutex_lock(&rate_ctrl_mutex);
	list_for_each_entry(alg, &rate_ctrl_algs, list) {
	if (!strcmp(alg->ops->name, name)) {
	ops = alg->ops;
	break;
	}
	}
	mutex_unlock(&rate_ctrl_mutex);
	return ops;
	}

	/* Get the rate control algorithm. */
	static const struct rate_control_ops *
	ieee80211_rate_control_ops_get(const char *name)
	{
	const struct rate_control_ops *ops;
	const char *alg_name;

	kparam_block_sysfs_write(ieee80211_default_rc_algo);
	if (!name)
	alg_name = ieee80211_default_rc_algo;
	else
	alg_name = name;

	ops = ieee80211_try_rate_control_ops_get(alg_name);
	if (!ops && name)
	/* try default if specific alg requested but not found */
	ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);

	/* try built-in one if specific alg requested but not found */
	if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
	ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
	kparam_unblock_sysfs_write(ieee80211_default_rc_algo);

	return ops;
	}

	#ifdef CONFIG_MAC80211_DEBUGFS
	static ssize_t rcname_read(struct file file, char __user userbuf,
	size_t count, loff_t *ppos)
	{
	struct rate_control_ref *ref = file->private_data;
	int len = strlen(ref->ops->name);

	return simple_read_from_buffer(userbuf, count, ppos,
	ref->ops->name, len);
	}

	static const struct file_operations rcname_ops = {
	.read = rcname_read,
	.open = simple_open,
	.llseek = default_llseek,
	};
	#endif

	static struct rate_control_ref rate_control_alloc(const char name,
	struct ieee80211_local *local)
	{
	struct dentry *debugfsdir = NULL;
	struct rate_control_ref *ref;

	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
	if (!ref)
	return NULL;
	ref->local = local;
	ref->ops = ieee80211_rate_control_ops_get(name);
	if (!ref->ops)
	goto free;

	#ifdef CONFIG_MAC80211_DEBUGFS
	debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
	local->debugfs.rcdir = debugfsdir;
	debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
	#endif

	ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
	if (!ref->priv)
	goto free;
	return ref;

	free:
	kfree(ref);
	return NULL;
	}

	static void rate_control_free(struct rate_control_ref *ctrl_ref)
	{
	ctrl_ref->ops->free(ctrl_ref->priv);

	#ifdef CONFIG_MAC80211_DEBUGFS
	debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
	ctrl_ref->local->debugfs.rcdir = NULL;
	#endif

	kfree(ctrl_ref);
	}

	static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
	{
	struct sk_buff *skb = txrc->skb;
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	__le16 fc;

	fc = hdr->frame_control;

	return (info->flags & (IEEE80211_TX_CTL_NO_ACK \|
	IEEE80211_TX_CTL_USE_MINRATE)) \|\|
	!ieee80211_is_data(fc);
	}

	static void rc_send_low_basicrate(s8 *idx, u32 basic_rates,
	struct ieee80211_supported_band *sband)
	{
	u8 i;

	if (basic_rates == 0)
	return; /* assume basic rates unknown and accept rate */
	if (*idx < 0)
	return;
	if (basic_rates & (1 << *idx))
	return; /* selected rate is a basic rate */

	for (i = *idx + 1; i <= sband->n_bitrates; i++) {
	if (basic_rates & (1 << i)) {
	*idx = i;
	return;
	}
	}

	/* could not find a basic rate; use original selection */
	}

	static void __rate_control_send_low(struct ieee80211_hw *hw,
	struct ieee80211_supported_band *sband,
	struct ieee80211_sta *sta,
	struct ieee80211_tx_info *info,
	u32 rate_mask)
	{
	int i;
	u32 rate_flags =
	ieee80211_chandef_rate_flags(&hw->conf.chandef);

	if ((sband->band == IEEE80211_BAND_2GHZ) &&
	(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
	rate_flags \|= IEEE80211_RATE_ERP_G;

	info->control.rates[0].idx = 0;
	for (i = 0; i < sband->n_bitrates; i++) {
	if (!(rate_mask & BIT(i)))
	continue;

	if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
	continue;

	if (!rate_supported(sta, sband->band, i))
	continue;

	info->control.rates[0].idx = i;
	break;
	}
	WARN_ON_ONCE(i == sband->n_bitrates);

	info->control.rates[0].count =
	(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
	1 : hw->max_rate_tries;

	info->control.skip_table = 1;
	}


	bool rate_control_send_low(struct ieee80211_sta *pubsta,
	void *priv_sta,
	struct ieee80211_tx_rate_control *txrc)
	{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
	struct ieee80211_supported_band *sband = txrc->sband;
	struct sta_info *sta;
	int mcast_rate;
	bool use_basicrate = false;

	if (!pubsta \|\| !priv_sta \|\| rc_no_data_or_no_ack_use_min(txrc)) {
	__rate_control_send_low(txrc->hw, sband, pubsta, info,
	txrc->rate_idx_mask);

	if (!pubsta && txrc->bss) {
	mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
	if (mcast_rate > 0) {
	info->control.rates[0].idx = mcast_rate - 1;
	return true;
	}
	use_basicrate = true;
	} else if (pubsta) {
	sta = container_of(pubsta, struct sta_info, sta);
	if (ieee80211_vif_is_mesh(&sta->sdata->vif))
	use_basicrate = true;
	}

	if (use_basicrate)
	rc_send_low_basicrate(&info->control.rates[0].idx,
	txrc->bss_conf->basic_rates,
	sband);

	return true;
	}
	return false;
	}
	EXPORT_SYMBOL(rate_control_send_low);

	static bool rate_idx_match_legacy_mask(struct ieee80211_tx_rate *rate,
	int n_bitrates, u32 mask)
	{
	int j;

	/* See whether the selected rate or anything below it is allowed. */
	for (j = rate->idx; j >= 0; j--) {
	if (mask & (1 << j)) {
	/* Okay, found a suitable rate. Use it. */
	rate->idx = j;
	return true;
	}
	}

	/* Try to find a higher rate that would be allowed */
	for (j = rate->idx + 1; j < n_bitrates; j++) {
	if (mask & (1 << j)) {
	/* Okay, found a suitable rate. Use it. */
	rate->idx = j;
	return true;
	}
	}
	return false;
	}

	static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
	{
	int i, j;
	int ridx, rbit;

	ridx = rate->idx / 8;
	rbit = rate->idx % 8;

	/* sanity check */
	if (ridx < 0 \|\| ridx >= IEEE80211_HT_MCS_MASK_LEN)
	return false;

	/* See whether the selected rate or anything below it is allowed. */
	for (i = ridx; i >= 0; i--) {
	for (j = rbit; j >= 0; j--)
	if (mcs_mask[i] & BIT(j)) {
	rate->idx = i * 8 + j;
	return true;
	}
	rbit = 7;
	}

	/* Try to find a higher rate that would be allowed */
	ridx = (rate->idx + 1) / 8;
	rbit = (rate->idx + 1) % 8;

	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
	for (j = rbit; j < 8; j++)
	if (mcs_mask[i] & BIT(j)) {
	rate->idx = i * 8 + j;
	return true;
	}
	rbit = 0;
	}
	return false;
	}



	static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
	struct ieee80211_supported_band *sband,
	enum nl80211_chan_width chan_width,
	u32 mask,
	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
	{
	struct ieee80211_tx_rate alt_rate;

	/* handle HT rates */
	if (rate->flags & IEEE80211_TX_RC_MCS) {
	if (rate_idx_match_mcs_mask(rate, mcs_mask))
	return;

	/* also try the legacy rates. */
	alt_rate.idx = 0;
	/* keep protection flags */
	alt_rate.flags = rate->flags &
	(IEEE80211_TX_RC_USE_RTS_CTS \|
	IEEE80211_TX_RC_USE_CTS_PROTECT \|
	IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
	alt_rate.count = rate->count;
	if (rate_idx_match_legacy_mask(&alt_rate,
	sband->n_bitrates, mask)) {
	*rate = alt_rate;
	return;
	}
	} else if (!(rate->flags & IEEE80211_TX_RC_VHT_MCS)) {
	/* handle legacy rates */
	if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
	return;

	/* if HT BSS, and we handle a data frame, also try HT rates */
	switch (chan_width) {
	case NL80211_CHAN_WIDTH_20_NOHT:
	case NL80211_CHAN_WIDTH_5:
	case NL80211_CHAN_WIDTH_10:
	return;
	default:
	break;
	}

	alt_rate.idx = 0;
	/* keep protection flags */
	alt_rate.flags = rate->flags &
	(IEEE80211_TX_RC_USE_RTS_CTS \|
	IEEE80211_TX_RC_USE_CTS_PROTECT \|
	IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
	alt_rate.count = rate->count;

	alt_rate.flags \|= IEEE80211_TX_RC_MCS;

	if (chan_width == NL80211_CHAN_WIDTH_40)
	alt_rate.flags \|= IEEE80211_TX_RC_40_MHZ_WIDTH;

	if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
	*rate = alt_rate;
	return;
	}
	}

	/*
	* Uh.. No suitable rate exists. This should not really happen with
	* sane TX rate mask configurations. However, should someone manage to
	* configure supported rates and TX rate mask in incompatible way,
	* allow the frame to be transmitted with whatever the rate control
	* selected.
	*/
	}

	static void rate_fixup_ratelist(struct ieee80211_vif *vif,
	struct ieee80211_supported_band *sband,
	struct ieee80211_tx_info *info,
	struct ieee80211_tx_rate *rates,
	int max_rates)
	{
	struct ieee80211_rate *rate;
	bool inval = false;
	int i;

	/*
	* Set up the RTS/CTS rate as the fastest basic rate
	* that is not faster than the data rate unless there
	* is no basic rate slower than the data rate, in which
	* case we pick the slowest basic rate
	*
	* XXX: Should this check all retry rates?
	*/
	if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
	u32 basic_rates = vif->bss_conf.basic_rates;
	s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;

	rate = &sband->bitrates[rates[0].idx];

	for (i = 0; i < sband->n_bitrates; i++) {
	/* must be a basic rate */
	if (!(basic_rates & BIT(i)))
	continue;
	/* must not be faster than the data rate */
	if (sband->bitrates[i].bitrate > rate->bitrate)
	continue;
	/* maximum */
	if (sband->bitrates[baserate].bitrate <
	sband->bitrates[i].bitrate)
	baserate = i;
	}

	info->control.rts_cts_rate_idx = baserate;
	}

	for (i = 0; i < max_rates; i++) {
	/*
	* make sure there's no valid rate following
	* an invalid one, just in case drivers don't
	* take the API seriously to stop at -1.
	*/
	if (inval) {
	rates[i].idx = -1;
	continue;
	}
	if (rates[i].idx < 0) {
	inval = true;
	continue;
	}

	/*
	* For now assume MCS is already set up correctly, this
	* needs to be fixed.
	*/
	if (rates[i].flags & IEEE80211_TX_RC_MCS) {
	WARN_ON(rates[i].idx > 76);

	if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
	info->control.use_cts_prot)
	rates[i].flags \|=
	IEEE80211_TX_RC_USE_CTS_PROTECT;
	continue;
	}

	if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
	WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
	continue;
	}

	/* set up RTS protection if desired */
	if (info->control.use_rts) {
	rates[i].flags \|= IEEE80211_TX_RC_USE_RTS_CTS;
	info->control.use_cts_prot = false;
	}

	/* RC is busted */
	if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
	rates[i].idx = -1;
	continue;
	}

	rate = &sband->bitrates[rates[i].idx];

	/* set up short preamble */
	if (info->control.short_preamble &&
	rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
	rates[i].flags \|= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;

	/* set up G protection */
	if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
	info->control.use_cts_prot &&
	rate->flags & IEEE80211_RATE_ERP_G)
	rates[i].flags \|= IEEE80211_TX_RC_USE_CTS_PROTECT;
	}
	}


	static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
	struct ieee80211_tx_info *info,
	struct ieee80211_tx_rate *rates,
	int max_rates)
	{
	struct ieee80211_sta_rates *ratetbl = NULL;
	int i;

	if (sta && !info->control.skip_table)
	ratetbl = rcu_dereference(sta->rates);

	/* Fill remaining rate slots with data from the sta rate table. */
	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
	for (i = 0; i < max_rates; i++) {
	if (i < ARRAY_SIZE(info->control.rates) &&
	info->control.rates[i].idx >= 0 &&
	info->control.rates[i].count) {
	if (rates != info->control.rates)
	rates[i] = info->control.rates[i];
	} else if (ratetbl) {
	rates[i].idx = ratetbl->rate[i].idx;
	rates[i].flags = ratetbl->rate[i].flags;
	if (info->control.use_rts)
	rates[i].count = ratetbl->rate[i].count_rts;
	else if (info->control.use_cts_prot)
	rates[i].count = ratetbl->rate[i].count_cts;
	else
	rates[i].count = ratetbl->rate[i].count;
	} else {
	rates[i].idx = -1;
	rates[i].count = 0;
	}

	if (rates[i].idx < 0 \|\| !rates[i].count)
	break;
	}
	}

	static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
	struct ieee80211_sta *sta,
	struct ieee80211_supported_band *sband,
	struct ieee80211_tx_info *info,
	struct ieee80211_tx_rate *rates,
	int max_rates)
	{
	enum nl80211_chan_width chan_width;
	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
	bool has_mcs_mask;
	u32 mask;
	u32 rate_flags;
	int i;

	/*
	* Try to enforce the rateidx mask the user wanted. skip this if the
	* default mask (allow all rates) is used to save some processing for
	* the common case.
	*/
	mask = sdata->rc_rateidx_mask[info->band];
	has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
	rate_flags =
	ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
	for (i = 0; i < sband->n_bitrates; i++)
	if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
	mask &= ~BIT(i);

	if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
	return;

	if (has_mcs_mask)
	memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
	sizeof(mcs_mask));
	else
	memset(mcs_mask, 0xff, sizeof(mcs_mask));

	if (sta) {
	/* Filter out rates that the STA does not support */
	mask &= sta->supp_rates[info->band];
	for (i = 0; i < sizeof(mcs_mask); i++)
	mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
	}

	/*
	* Make sure the rate index selected for each TX rate is
	* included in the configured mask and change the rate indexes
	* if needed.
	*/
	chan_width = sdata->vif.bss_conf.chandef.width;
	for (i = 0; i < max_rates; i++) {
	/* Skip invalid rates */
	if (rates[i].idx < 0)
	break;

	rate_idx_match_mask(&rates[i], sband, chan_width, mask,
	mcs_mask);
	}
	}

	void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
	struct ieee80211_sta *sta,
	struct sk_buff *skb,
	struct ieee80211_tx_rate *dest,
	int max_rates)
	{
	struct ieee80211_sub_if_data *sdata;
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_supported_band *sband;

	rate_control_fill_sta_table(sta, info, dest, max_rates);

	if (!vif)
	return;

	sdata = vif_to_sdata(vif);
	sband = sdata->local->hw.wiphy->bands[info->band];

	if (ieee80211_is_data(hdr->frame_control))
	rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);

	if (dest[0].idx < 0)
	__rate_control_send_low(&sdata->local->hw, sband, sta, info,
	sdata->rc_rateidx_mask[info->band]);

	if (sta)
	rate_fixup_ratelist(vif, sband, info, dest, max_rates);
	}
	EXPORT_SYMBOL(ieee80211_get_tx_rates);

	void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
	struct sta_info *sta,
	struct ieee80211_tx_rate_control *txrc)
	{
	struct rate_control_ref *ref = sdata->local->rate_ctrl;
	void *priv_sta = NULL;
	struct ieee80211_sta *ista = NULL;
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
	int i;

	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
	ista = &sta->sta;
	priv_sta = sta->rate_ctrl_priv;
	}

	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
	info->control.rates[i].idx = -1;
	info->control.rates[i].flags = 0;
	info->control.rates[i].count = 0;
	}

	if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
	return;

	ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);

	if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
	return;

	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
	info->control.rates,
	ARRAY_SIZE(info->control.rates));
	}

	int rate_control_set_rates(struct ieee80211_hw *hw,
	struct ieee80211_sta *pubsta,
	struct ieee80211_sta_rates *rates)
	{
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	struct ieee80211_sta_rates *old;

	/*
	* mac80211 guarantees that this function will not be called
	* concurrently, so the following RCU access is safe, even without
	* extra locking. This can not be checked easily, so we just set
	* the condition to true.
	*/
	old = rcu_dereference_protected(pubsta->rates, true);
	rcu_assign_pointer(pubsta->rates, rates);
	if (old)
	kfree_rcu(old, rcu_head);

	drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);

	return 0;
	}
	EXPORT_SYMBOL(rate_control_set_rates);

	int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
	const char *name)
	{
	struct rate_control_ref *ref;

	ASSERT_RTNL();

	if (local->open_count)
	return -EBUSY;

	if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
	if (WARN_ON(!local->ops->set_rts_threshold))
	return -EINVAL;
	return 0;
	}

	ref = rate_control_alloc(name, local);
	if (!ref) {
	wiphy_warn(local->hw.wiphy,
	"Failed to select rate control algorithm\n");
	return -ENOENT;
	}

	WARN_ON(local->rate_ctrl);
	local->rate_ctrl = ref;

	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
	ref->ops->name);

	return 0;
	}

	void rate_control_deinitialize(struct ieee80211_local *local)
	{
	struct rate_control_ref *ref;

	ref = local->rate_ctrl;

	if (!ref)
	return;

	local->rate_ctrl = NULL;
	rate_control_free(ref);
	}